7 replies to this topic

[JamesGodfrey1992]

What are the size of bolts required for fitting the seat subframe to the chassis? It looks i need 2 thin type bolts and 2 thicker sized ones. 

 

If anyone knows the length and thread size required i'd be most grateful for the help. 

 

 

 

 

 

[ado15]

If you mean the bolts holding the seat brackets to the front of the crossmember, they are all 1/4" UNF.  3/4" long would be plenty.

[tiger99]

I agree. Make sure they are at least grade 8.8, as they are quite small bolts, and do take some fatugue loading, especially from heavy drivers like me!

 

If there seem to be two large and two small, it may be that someone has stripped a couple of the captive nuts and re-tapped them, which is naughty, as there is not enough metal to do that properly. If so, report back, if possible with a picture, and someone here will be able to advise further. Such things can be repaired, as indeed can anything on a Mini, but it is somewhat tedious at times.

[Tamworthbay]

I agree. Make sure they are at least grade 8.8, as they are quite small bolts, and do take some fatugue loading, especially from heavy drivers like me!
 
If there seem to be two large and two small, it may be that someone has stripped a couple of the captive nuts and re-tapped them, which is naughty, as there is not enough metal to do that properly. If so, report back, if possible with a picture, and someone here will be able to advise further. Such things can be repaired, as indeed can anything on a Mini, but it is somewhat tedious at times.

I wouldn't use an 8.8 grade as the metric bolt will damage the hole but a grade 5 would do the trick. Useful guide to grades here:

http://www.boltdepot...rade-chart.aspx

[tiger99]

Well, actually, the oldest BS bolts in Minis would be Grade S, which effectively is the same as grade 5 or 8.8. My first, and probably second, Minis had Grade S bolts, the most recent had 8.8, because there is no reason why UNF or UNC bolts can not be grade 8.8, in fact almost all of the good ones are now. Some of course are mild steel, or stainless, neither of which are suitable here, and a few are 10.9 (OK) or 12.9 (NOT RECOMMENDED here, lacking ductility). If you fancy capheads (no good reason why not), they will be 10.9.

 

But then it gets even more controversial, will it take an imperial or metric Allen key? And what if you want a Torx or Spline head on a Unified thread, is it possible, or "legal", i.e. within any published spec, and does anyone make it? Would it have a metric head on an imperial shank? I wish I knew, as I can see a couple of places on a Mini where Torx, in particular, could be very useful.

 

Bolt Depot is a US company, and may not have access to all that we are used to here. They possibly never had seen BS grade S, as there was no reason to ever stock BS bolts in the US, because an ANSI "unified" bolt was effectively the same anyway. 8.8 UNF bolts are easy to find in the UK, for instance Namrick has them.

[Tamworthbay]

Well, actually, the oldest BS bolts in Minis would be Grade S, which effectively is the same as grade 5 or 8.8. My first, and probably second, Minis had Grade S bolts, the most recent had 8.8, because there is no reason why UNF or UNC bolts can not be grade 8.8, in fact almost all of the good ones are now. Some of course are mild steel, or stainless, neither of which are suitable here, and a few are 10.9 (OK) or 12.9 (NOT RECOMMENDED here, lacking ductility). If you fancy capheads (no good reason why not), they will be 10.9.
 
But then it gets even more controversial, will it take an imperial or metric Allen key? And what if you want a Torx or Spline head on a Unified thread, is it possible, or "legal", i.e. within any published spec, and does anyone make it? Would it have a metric head on an imperial shank? I wish I knew, as I can see a couple of places on a Mini where Torx, in particular, could be very useful.
 
Bolt Depot is a US company, and may not have access to all that we are used to here. They possibly never had seen BS grade S, as there was no reason to ever stock BS bolts in the US, because an ANSI "unified" bolt was effectively the same anyway. 8.8 UNF bolts are easy to find in the UK, for instance Namrick has them.

I am very lucky to have CW fasteners a stones throw from me, they are a brilliant old fashioned fastener place. If they can't get it then nobody makes it. They are very traditional (down to the grumpy guy on the desk) but an absolute hive of information. Unfortunately their website is rubbish, but if anyone wants bits at cheaper than Namrick prices, or just good advice then I would give them a ring. Sadly getting good quality stuff is very hit and miss in a lot of places as the likes of screw fix and B&Q have taken over that only stock bolts in cream cheese grade.

Website for CW in case anyone is interested:

http://www.cwfasteners.co.uk

[tiger99]

That is a useful link, thanks! I really like old-fashioned companies like that, with knowledgable but grumpy staff.

[Tamworthbay]

That is a useful link, thanks! I really like old-fashioned companies like that, with knowledgable but grumpy staff.

To be fair there are four guys there and three are great but one is a miserable sod. If I ring up and get him I usually ask a stupid question and ring off then ring back a few minutes later. The shop is brilliant, it's an industrial unit and you walk into a tiny space with an age old wooden work top, you ask for whatever you need and they disappear behind with sounds of rummaging. It's like going back 50 years in some ways but they have never ever let me down and don't have a minimum order, so even if you only want one bolt they are still happy to help. They do Mail order so can supply anywhere, not just the local area.